Email Deliverability Auditor

Your emails are going to spam and you don't know why. Your customers aren't getting password resets. Your marketing emails have a 12% open rate when it should be 40%. You've tried everything and nothing works.

This MCP server tells you exactly what's wrong and exactly how to fix it.

Here's the problem in plain English: when you send an email, the receiving server (Gmail, Outlook, Yahoo) runs three invisible checks before deciding whether to deliver it to the inbox, junk it, or block it entirely. If you fail any of them, your email disappears and you never get told why. This tool shows you what those servers see when they look at your domain.

What each check actually tells you:

SPF -- "Am I allowed to send email from this domain?" You publish a list of servers authorized to send your email. If your sending service (Mailchimp, SendGrid, your own server) isn't on that list, everything you send looks like a forgery. This tool reads your SPF record, follows redirect chains, and tells you if you're accidentally blocking your own legitimate email.

DKIM -- "Can I prove this email wasn't tampered with?" Every email you send should carry a cryptographic signature. If you don't have DKIM set up, your emails have no proof of authenticity. Receiving servers treat unsigned email as suspicious. This tool scans common DKIM selectors and tells you if your emails are being signed or going out naked.

DMARC -- "If something fails, what should the receiving server do?" This is your policy that tells Gmail and Outlook what to do when SPF or DKIM fails: nothing (monitor), send to spam (quarantine), or block entirely (reject). Without DMARC, anyone can spoof your domain and you have no way to stop it. This tool reads your policy and tells you if you're actually protected or just monitoring.

MX -- "Where does my email actually go?" Your MX records tell the world which servers handle your incoming email. Wrong MX records mean lost email. No redundancy means downtime. This tool shows your mail routing at a glance.

SMTP -- "Is my mail server even responding?" Connects to your mail server, reads the banner, checks if STARTTLS encryption and authentication are enabled. A safe test -- no email is ever sent. You find out in seconds if your server is misconfigured before your users tell you.

Blacklists -- "Am I on a spam list?" Checks your IP against Spamhaus, SpamCop, UCEPROTECT, AbuseAT, and PSBL. Being on even one blacklist explains why certain providers block you. Being on all of them means you need to fix something immediately.

The full deliverability check runs all of these at once and gives you a letter grade from A to F with prioritized recommendations. Here's what it looks like for gmail.com (we test against known domains to prove the tool works -- you run it against YOUR domain):

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Overall Grade: B (75/100)

SPF: [PASS] Present Authorized: 2 IPv4 ranges, 6 IPv6 ranges Policy: ~all (softfail)

DKIM: [FAIL] Not found Tried selectors: google, gm1, gm2, selector1, selector2

DMARC: [PASS] Present (p=none -- monitoring only) Reports to: mailauth-reports@google.com

MX: [PASS] 5 mail servers SMTP: [PASS] Reachable, STARTTLS enabled Blacklists: [PASS] Clean on all 5 lists

Recommendations: [HIGH] Add DKIM signing for email authentication [LOW] Move DMARC from p=none to p=quarantine or p=reject

If you run this against your own domain and see DKIM: [FAIL] and DMARC: missing, you now know exactly why your emails go to spam and exactly what to fix. Fix those two things, rerun the tool, and watch your grade go from D to A.

No paid APIs. No configuration. No DNS expertise required. Just ask the AI "audit mydomain.com" and it tells you everything.

Free: 50 checks per day. Pro ($9/mo): 500 checks per day. All 7 tools included on both plans.